A cobpobation of new yobk



' BATTERY CHARGER original Filed August 19, 1922 3 sheeisheet 1 y E. w. ENGLE BATTERY CHARGER Y f @dv Original Filed August y19. 1922 3 Sheets-Sheet 2 Oct. 12 1926.

oct. 12 192s'.

E. W. ENGLE BATTERY CHARGER 3 Sheets-Sheet :5

Original Filed August 19I 1922 Reiued Oct. 12, 1926.

UNITED STATES BATTERY CHARGER.

Original applications led August 19, 1922, Serial No. 582,851, and October 16, .1923, Serial No. 868,938. Continued and application led Hatch 27, 1924,8eria1 No. 702,278. Original No. 1,495,582, dated May 27, 192i Application tor reime led Hay 21, 1925. Serial No. 32,492.

to a battery nnting current storage batteries of the character used in connection with automobile starting and lighting systems and radio equipment.

The object of the invention is to provide an improved battery charger which will be ellicient and noiseless in operation, which will have a substantially constant charging rate, and which will be simple and durable in construction.

Other objects and advantages will appear from time to time as the description of the invention progresses.

This application is a continuation of my applications Serial Nos. 582,851,1iled August 19, 1922,`and 668,938, filed October 1G, 1923.

It is' believed the invention 4will be understood most readily from adetailed description thereof taken in connection with Athe accompanying drawings, in which- Figure 1 is a plan view of the complete charging unit;

Figure 2 is a section on line 2-2 of Figure 1;

Figure 3 is a section on line 3-3 of Figure 1;

Figure 4 is a section on line 4 4 of Figure l; Q

Figure 5 schematically indicates the circuit connections of the various elements of the battery charger, and

Figure 6 schematically indicates the construction and arrangement of the transformer core andcoils.

Referring now to the drawings, in which like reference characters indicate like Darts in the several views, 10 indicates the charger container of wood or other suitable material. The container 10 is provided with a bail 11 and the supporting legs or pads 12 of rubber or other suitable material. The container is provided at the top and substantially centrally thereof with the transversely extending strip 13 which forms a partial partition between the portion of the container in which is positioned the rectifier cell and the portion in which the transformer and similar elements are positioned.

The rectfying element of the present inof by the ends of the cell engaging the con- Re16,43s PATENT OFFICE.

nssreNon To rms'rnnx. rnonuc'rs A conronnron or NEW Yonx.

vention consistsl of an anode 14 of lead, and a. cathode 15 of tantalum in an electrolyte, preferably of dilute acid, as sulphur-ic acid. Sulphuric acid of 1.25 specific gravit has been found satisfactory. It has been ound that tantalum has the property of permitting current to flow from the electrolyte to the tantalum electrode, but preventing the flow of electricity in the reverse direction. Theelectrolyte is confined in a cell 16 of lead in the present embodiment of the invention, although it may be of other satisfactory material as hard rubber. vThe anode 11 preferably has a small amount of antimony mixed with the lead in order to make it more resistive to the action of the electrolyte. lf a Ahard rubber cell is employed, it may be fitted within a casing of lead or similar material having heat radiating flanges.

Fixed to the bottom of the cell 16, or integral therewith, are the downwardly' extending supporting members 17, each of `which is provided with a pair of laterally extendingfeet 18 securedto the bottom of the container 10 by means of the bolts 19. The Sides of the cell 16 are provided with the laterally extending heat radiating wings or flanges 20 which 'act -to position the cell 16 between one side of the container 10 and the partition member 13. The cell is positioned against movement lengthwise theretainer. Positioned between pairs of the flanges 2() are the laterally extending shelves 22, each pair of which is provided with aligned openings 23 within Which are fixed the insulator 24 of porcelain or other desired material.

The top of the cell 16 is provided with a cover '25 of hard rubber or othery suitable material. The plate 25 is provided With a filler cap opening 2G within which is inserted the cap 27 having the vent openings 28 therein. T-he cover 25 is also provided with the tapered openings 29 and 30. Positioned within the opening or recess 29 is the sleeve 32 of hard rubber or other Isuit-able material.v The sleeve A32 is externally threaded at its lower end and is provided with the nut 33 by means of which the sleeve 32 is firmly secured in position. Extending longitudinally of the sleeve 32 is the recess 34 which terminates at the lower end thereof in the rectangular opening 35 through which the cathode 15 extends. The upper end of the cathode 15 is cast in or otherwise secured to the lower end of the terminal post 31. A satisfactory mannerof securingI the tantalum is as follows:

' A composition of lead containing antrmony will expand upon cooling. About 6% of antimony has been found to give good results. If the terminal post 31 of the leadantimony-compound is'` cast"l about the end of the tantalum strip, the'outside hardens first, due to contact with the mould. This forms a restraining envelope withinrwhich 'is the still liquid metal surounding the tantalum strip.

As this inner molten metal hardens, it tends t0 expand, but being restrained by the outer shell, the end of the cathode is firmly gripped by the lead. The terminal post 31 is provided with an annular ridge 36. The post 31 and the cathode 15 are secured in position as follows:

The recess 34 having been filled with an acid-resisting com ound, as asphaltie cement, the lower en of the post 31 is forced into the top of the recess34 before the cement has hardened. After the post 31 has been put in position, as just described, the top portion of the recess 29 is also filled with battery sealingcement in order firmly Vto-anchor the post 31. Surrounding the cathode 15, adjacent to the lower end thereof, is a block 37 of acid-resisting material,

as soft rubber, which is maintained in position by means of the portions 38 turned from thelower end of the cathode 15.

The bottom of the cell-16, adjacent to one Th one thereof, is provided with the annular ange 39 within which is. positioned theI lower end of the anode 14, a collar 40 of insulating material, as hard rubber, being provided between the flange 39 and the anode 14 in order to revent engagement. The anode 14 is provi ed with an. enlarged portion or bead 41 which engages the top of the collar 40 in order to support the anode. The upper end of the anode 14 passes upwardly through the ta ered recess 30 andjis provided with a iimge 42 which engages the bottom of the cover 25. The space within the recess 30 about the upper end 43 of the anode 14 is filled with an acid-resisting cement, as asphaltic cement.

Secured to the upper ends of the terminal posts- 31 and 43, respectively, are the rods" 44 and 45 of lead or other 'conductinglmaterial which extends laterally and then downwardly through the insulating sleeves 24.

The transformer consists 'of the core member formed of the E-shaped laminations 46 and 47 about the tongues of which are positioned the primary coil 48 and the secondary coil 49. The transformer shown` com- Positioned onopposite sides of the l'amlnations 46`and 47 are the clamping members 50 which areheld firmly in engagement with the laminations by means of thebolts 51.l

The lower ends 'ofthe members 50 `,aregprovided'with the laterally extendin perforated portions 52 which -are Isecure to the bottom of. the container 10`by means of the This transformer when screws 53,. The upper ends of the clamping members 50 are provided with the laterally extending portions 54, each' of which is provided wlth a screw threaded opening 55. Positioned on the laterally extending portions 54 is (a plate 56 of bakelite,'f libre, or other suitableinsulating material which is secured to the vportions 54 by means ,of the screws 5 7 Iwhich pass downwardly through the plate 56 and into the screw threaded openin s 55. The fuse cli S158 and 59 are secure to the. top of the p a'te 56-by means of the bolts 60 and 61, respectively, provided with the securing nuts 62 and 63.

Fixedto lthe transformer core, in any desired manner, or otherwise mounted is ay approximately .025 in diameter, and a uta 161/" in length. After the coil 66 has been placed 'in'positiom the ends of the sleeve 65 are closed by some suitable mineral'cement.

is acts partially to retain the heat generated by the coil and causes its pro erties to be more constant. Nickel wire as been found preferable because it offers increased resistance upon increase of the current flow. The purpose of the coil 66 is to tend to limit and malntain constant .the current flow through the rectifier. One end of the wire 66 is joined to the fuse clip 58 .by means of the conductor 67, the other end being joined tothe secondary 68 of the transformer by meansof the conductor69 (see F-igur'es4 and 5). Theother fuse clip 59 is jolned to the rod 44 connected to the tantalu'ml cathode by means of the lconductor 70.' Positioned within thel clips 58 and 59 is vthe i:n'dinary cartridge fuse 1 such as is employed in conmobilesl and other devices. y

A fuseof about 6 am res is employed and acts to open the circuit if the ,charger reversely connected to th'ebattery or if a short circuit is established, and thus protects the charger'from injury as'well as actin as an alarm if the c joined to the battery. l

The electrical connections of the battery` charging device will be more specifically harger is improperly',

nection with 'the electrical circuitpe'offfautoeigo' y by means of the conductor pair 76 to the.

described, reference made to Ifigure 5. The primary of the transformer 1s jolned ordinary plug 77 whichis adapted to be inserted in the socket 78, the terminals of which are joined t0 the conductors 79 and 80 of the ordinary light circuit Vof approximately 110 volts alternating current. YOne end of the secondary 68 is joined'byvmeans of the conductor 81 to the terminal clip 82. The other end of the secondary 68V is' joined by the conductor 69 to the resistance 66, as previously described. The opposite end of the resistance 66 is connected by the conductor 67 to one end-of the fuse 71,-the opposit/el end of 'the fuse 71 being'joined by conductor 70 tothe tantalum cathode 15. The lead anode is oined by the conductor 83 to the terminal c ip 84. The winding 68, the limiting coil 66 and the resistance of the transformer operate to limit the flow of current to a'.' maximum of approximately 31,@ amperes direct current.

It will be noted that the transformer limits the voltage to current is owing in the one direction permitted b the rectifier, but also when the current ten s to flow in the other direction. In other words, the transformer limits the voltage 'whether there is Iactual current flow or not. The building up of excessive voltage across the rectifier urng the non-current eriod is precluded. This protects the recti er, which would yotherwise soonldisintegrate and break down if `subjected to ex.

cessive voltage. Such would be the case if, for example, the resistance 68 were relied on to limit both the amperage and the voltage.

By reference to Figure 2, it will be noted that the conductor 83 is joined to the lower end of 'the rod 45 connected to the anode 14 and extends laterally and then upwardly through the opening 85 in the plate 56. The conductor 81 which extends from one end of the secondary 68 passesup'wardly and out through the opening 86 in the plate 56. The pair 76, the conductors of which are joined to the o posite ends of the primary 75, passes u war ly through the opening 87 in the p ate 56. The plate 56,'Lin addition to the openings 85, 86 and 87 is provided with a plurality of openings 88. The sides of vthe container 10, adjacent to the bottom thereof, are provided with the openings 89. As shown, the openings 89 lare provided only on two opposite sides of the box, but, if desired, they m'ay be .provided on all four sides. It will be noted that the cell 16 and also the transformer structure are maintained spaced from the bottom of the container. Thls arrangement permits through freely through air to enter the container the openings 89 and pass'upwardly about the transformer and out the holes 88 in plate 56and also upthe rectifier not only when the of the rectifier is materially increas age was applied.

wardly between the win for fianges 20 of the cell, thus greatly assisting in maintaining the charger cool while it is'in use, which is quite essential to the mostsatisfactory operation. y

It has been, found that when the transformer employed .with the rectifier, such as `herein shownis designed. to give a certain chargingrrate,y oftentimes the charging rate of' the rectifier willsuddenly; change.A This is believed lto be due`generally. to some foreign matter havi been introduced into the electrolyte. App icant has .'discovered, that when a small quantity of metallic impurity, as for instance iron, is added to the elec.- trolyte of dilute acid such as sul or phosphoric acid, this tendency oft lechar" lng rate to fluctuate is largely obviate Very goodl results are obtained by adding from one-half to one kpart'zver thousand of iron. The iron may be ded as metalliciron,.but is'preferablyintrodueed in the form.v of ferrous sulphate. It .has been found that ag slight excess of iron may be added to the electrolyte without injuriously afiectin the rectifier. In practice the ironis intro uced by adding about one gram of ferrous sulphate crystals to'each 100 cubic centimeters of the electrolyte. Somewhat larger or .smaller quantities of iron may be added with varying results. When the iron impurity is added to the electrolyte, the char-gierig rate usually in the neighborhood of 50%, althou h sometimes much larger increases are broug t about. In addition to increasing the charging rate, the addition ofthe iron to the electrolyte causes the heating effect of the rectifier to be relatively decreased; i This is prob'- ably due to the?, iron acting to decrease the internal resistance ofthe rectifier.

In addition' to increasing the chargin rate and decreasing the 'relative heating e feet, the introduction of the metallic Jimpurity acts to render the. rectifier ,more stable or constant in its char 'ng rate. When the rectifienis'operated wlthoutthe ferrous sulfate addition to the electrolyte an excessfv'oltage or excess current ap lied for a very short time so changes lthey characterlistis of the film on the tantalum4 that when the voltage 1s again reduced to normal the current willnotbe thesame as before the excess voltage but will be materially less, but when ferrous sulfate or other beneficial metallic additions are included in the electrolyte an excessivoltage applied for a. short time does not upon resumption to normal voltage prevent the current from returning to the same v alue as before the excess volt- While iron has been found to give -very good results when introduced into .the electrolyte, applicanthas discovered that cer'- tain other metallic impurities, as copper or explosion of t 'laf otherwise would occur 'at one of the elec? the explosions.

ed 'the explosions are .absolutely in addition to preeva eration.

silver, beval-toa certain extent,"the same e'ect as'iron when added to the electrolyte.

It' has been found that a rectier constriited as above described will sometimes ex lode under exceptional circumstances, as when'subjected to an overload.- This mag be due to the union of the hydrogen an oxygen liberated` been discovered Ythat if a small amount' of heavy oil is; ured into the rectifier cell, the e cell is absolutely prevented. About two teaspoonfuls of pure heavy liquid petrolatum has been extensively employed -with satisfactory results. The heavy oil orms a'lilm yover'the top'of the electrolyte and also an insulating. film on the electrodes. This film may act tosuppress sparks which trodes, or perhaps the film the electrolyte retards the escape of lthe gas responsible for Atany rate, when the oil is emplo prevente The oillilm, vventing explosions, practically preventsfuming of the electrolyte and greatly reduces e batter charger herein disclosed has beeni'designe to charge either 61.0r 12 volt batteries. When employed in charging a 6 'volt battery, it provides a maximum 'charging current of about 31/2 amperes, and when used with a 12 volt battery, its charging rate is about l ampere.

1f a battery charger of the character here-- in disclosed 1s employed in. connection with an electric power circuit, the voltage of which varies "greatly from 110 volts, the transformer should -be altered to give an output current similar ,to 'thathe'rein described.

.y While in the drawings and in the above description, applicant has disclosed but a single set of details which s how the preferred embodiment of his invention, it is to be understood that various. .modifications are contemplated andA the linvention should, therefore, lbe limited merely by the scope of the appended claims..

Having l thus described .my` what I claimas new 'and desire to secure by Letters Patent of the United States isz,v

1. An electrolytic rectifier-for producing unidirectional current fromy a' source of alternating current, said rectifierhavingan electrode of tantalum and an electrode ofl a non-filming conductor in an acid electrolyte addition.

invention,v

.and oneA half mass containing a small percentage of metallic 2. An electrolytie rectifier. having electrodeof tantalum, an electrode of' lead and an electrolyte of dilute sulphuric acid and means to limit the current to substantially y three and one-half amperes passing between at the electrodes; It has said electrolyte and said -tantalum electrode. 3; A charger including a 'source of alternating current, such as a transformer winding. having an'etlective voltage 'of substantially veighteen and one-half lvolts, a tantalum electrode, a 'dilute sulphuric acid electrolyte, a non-filming electrode. and conductor means for connecting said elements in series with a battery to be charged.

' 4. In' a battery lcharger,l an electrol tic A'rectifier including 'a tantalum electrode 1n a .dilute sulfuric acid, electrolyte having a small quantity of metallic impurity added thereto. i

In a battery charger an electrolytic rectifier including a tantalum` cathode in an acid electrolyte, a' cell containing said el'ectrolyte, 'ii terminal post of le'ad-antimony composition for said cathode, one end of said cathode being cast into said terminal post, a cover for said cell provided with a sleeve in which are positioned the adjoining ends of said cathode and post, and an acid resisting cement within said sleeveabout said cathode below said post.

6. An electrolytic valve including a tantalum electrode in an acid electrolyte having a small quantity of iron ,added thereto.

7. An electrolytic rectifier including a tantalum electrode in a dilute sulphuric acid electrolyte having a small quantity of iron added thereto.

8. An electrolytic rectifier for converting lalternating current into. unidirectional current including a tantalum electrode in an electrolyte of sulfuric acid diluted to substantially 1.25 specific gravity.

'9. The method of operating a rectifier having a tatalum electrode in an electrolyte,`

effective, alternating potential of eighteen andl one half volts or less, and maintaining the resistance -'of the circuit such that the .effective pulsatingI current between said electrode and electrolyte will -not exceed three ampe'res.

In witness whereof, I hereunto subscribe my name this 27thdavof April, 1925. EDGAR-W. ENGLE. 

